To insert content into the accordion layout, edit the document where it is placed on the Design tab of CMS Desk and make sure that the Display web part content option is enabled (using the checkbox in the header of the tab menu). This way, you can select individual panes and add any web parts that you need into the corresponding zones.
Help URL: http://devnet.kentico.com/docs/webparts/index.html?AccordionLayout_overview.htm